190 CARB0XIFP:R0US cephalopoda of IRELAND. 



Tliis relationsliip shows itself in the case of G. (B.) Darisi in the acute periphery, 

 and in both species in the presence of the lateral crest indicated in the ornaments 

 of the test. The deep and angular-margined umbilicus in G. (B.) reticulatum and 

 G. (B.) Davisi is also paralleled in G. (B.) cordatum. 



Remarks. — The on\j individuals of this species known to me, two in number, 

 were obtained in the great quarries of Little Island which overlook one of the lower 

 reaches of the river Lee, about four miles below the city of Cork, locally known as 

 Lough Mahon. Both specimens are distorted, the one whose dimensions are given 

 above much less so than the other, which is stretched out into a long ellipse, whose 

 greater diameter would be at least double that of the normal diameter of the shell. 

 Such is the condition of many of the fossils in the Carboniferous rocks of the south 

 of Ireland, these rocks having untlergone severe pressure, which has thrown them 

 into numerous folds and dislocations, involving the distortion of the fossils contained 

 in them. 



LocaJitij. — Little Island, near Cork. 



Glyphioceras (Betrichoceras) pull'Hellum, sp. nov. Plate XLIX, fig. 5. 



Description. — Shell rather small, somewhat inflated, umbilicated ; height of 

 outer whorl rather more than half the diameter of the shell. Whorls apparently 

 few in number. Inclusion nearly complete. Umbilicus one-fifth of the diameter 

 of the shell, deep, iufundibuliform, with steep sides and subangular margin. Whorl 

 bluntly sagittate in section, apparently a little wider than high, l)ut the exact pro- 

 portions cannot be determined, as only one-half of the shell is free from the rock ; 

 indented to about three-eighths of its height liy the preceding whorl. Periphery 

 narrowly rounded. Lateral area regularly convex, appearing in profile as a \evj 

 broad and spreading arch ; becoming a little depressed in the uj)per half near the 

 aperture. Test ornamented with very fine but perfectly distinct thread-like lines, 

 apparently with crenulations ; proceeding from the umbilicus the}'' pursue at first a 

 nearly straight course, but soon make a slight curve backwards, then curving boldly 

 forward tliey pass over the periphery in a strong l)ackwardly directed curve, thus 

 forming a deep sinus in that region. Towards the aperture the anteriorly directed 

 curve becomes narrower and more tongue-like in form, and the lines have here a 

 tendency to form little bundles, which cause them to stand out more prominently. 

 Two narrow and sliallow constrictions, which conform in direction to the lines of 

 the ornamentation, are developed iipon the test. Verj^ faint spiral lines ai-e seen 

 covering the test all over. (It must not be supposed that these lines produce the 

 effect of reticulation : they can only be seen with a lens ; the transverse lines are 

 easily discernible without such aid.) Body-chamber and septa unknown. 



